Although hypodermic syringes may be used for blood sample collection purposes vacuum tube phlebotomy, where one or more samples of a patient's blood are successively drawn into respective evacuated blood collection tubes by way of a double ended hypodermic needle has become the procedure of choice.
Typically, this is currently done with a needle having two sharp ends, mounting the needle in a generally cup-shaped holder, and placing a previously-evacuated collection tube into the holder so that the proximal end of the needle cannula pierces an elastomeric seal of the tube after the opposite needle end has been inserted into the patient's vein. As soon as the proximal needle cannula pierces the tube, the vacuum therein draws blood from the vein, through the needle, into the tube. When sufficient blood has been collected, the pre-evacuated tube is withdrawn from the needle cannula. Often, one or more additional evacuated tubes are inserted into the holder. After the desired number of samples have been drawn, the needle is withdrawn from the vein and discarded.
After use the needle must be disposed of, typically by first removing it from the blood collection tube holder, recapping it, and then inserting it into a Sharp's receptacle. To prevent the reuse of the needle it is sometimes broken. However, this has been found to cause aerosol contamination frequently. Health care workers are susceptible to accidental and potentially infectious needle strikes when they dispose of contaminated needle cannula after use. This can expose them to a communicable disease such as AIDS or hepatitis B. To avoid infections, health care workers are now instructed neither to recap contaminated needles nor to "manipulate contaminated needles by hand," but rather to dispose of them in Sharp's containers, molded plastic receptacles provided specifically for receiving waste which is potentially biologically hazardous, from blood precautionary patients.
Even these improved procedures do not fully protect the health care worker from accidental needle strike and the possibility of being accidentally exposed to a communicable disease as the act of inserting a contaminated cannula into the Sharp's container may itself result in accidental needle strike. The worker must still handle potentially contaminated needles because the cup-shaped holders for receiving the needles are typically reused, often as much as two hundred times, until the threads into which the needle is screwed become worn. In addition, the Sharp's containers are often not near enough to the location of use, causing the health care worker to carry the potentially contaminated needles to the disposal container. At other times, the health care worker may simply choose to dispose of the needle wherever and whenever most convenient, where an exposed and contaminated needle cannula in an unexpected location may pose yet a further health hazard.
The virtually unavoidable mini-accidents caused by accidental needle strikes have become a particularly serious concern since the spread of the AIDS disease, which has, in fact, been transmitted in this manner. Thus, a blood test for such diseases as AIDS and hepatitis B is now required whenever such an accident occurs. The necessary testing of health care workers who have received an inadvertent needle strike has thereby led to considerable additional costs.
Recently the assignee of the present invention has developed a safety blood collection tube holder, which is the subject of another, currently pending patent application. Briefly, such a safety holder has a needle/vacuum tube carrier which is slidably disposed within a tubular sleeve. The carrier is freely movable between first and second positions in which the needle projects from the housing or is encapsulated within the housing so that it cannot be directly contacted by health care workers. The carrier cannot be returned to its first position therefore the used needle cannula is never again exposed. So long as a contaminated needle cannula is extended in an unshielded condition it poses a potential infection hazard.